The present invention relates to the field of water-in-oil solid emulsions for caring for and/or treating and/or making up human skin, including the scalp, and/or the lips, which are especially in the form of a cast makeup product and in particular a makeup stick such as lipsticks or foundations. They may especially be makeup and/or care compositions for the skin and/or the lips, antisun compositions and hygiene compositions, for instance deodorants.
In the cosmetics field, water-in-oil emulsions are commonly used since they especially allow active agents to be conveyed in the aqueous phase and give a sensation of freshness during and after application. Conventional water-in-oil emulsions contain one or more surfactants and an oily phase. They may also comprise a waxy phase. The waxy phase serves especially to structure the water-in-oil emulsion in order especially to obtain a stick therefrom. To do this, the wax particles create between themselves a network established by connecting the wax particles together, and it is this network that gives the product cohesion.
In general, conventional solid water-in-oil emulsions cannot contain a high proportion of aqueous dispersed phase, i.e., more than 50% by weight, without the risk of significantly impairing the expected mechanical properties.
Thus, patent application EP 1 064 908 describes solid cosmetic compositions of inverse emulsion type containing less than 30% by weight of water stabilized with an emulsifier from the carboxy-alkyl-polyglycerol family, and a fatty phase whose liquefaction point is greater than 60° C. Patent application JP-A-03 261 707 describes solid cosmetic emulsions containing silicone oils, waxes with a melting point equal to 80° C., water and at least one emulsifier of dimethicone copolyol type. Patent application WO 99/47111 describes solid cosmetic compositions of the water-in-oil emulsion type comprising less than 40% by weight of an aqueous phase emulsified using a silicone surfactant of alkyldimethicone copolyol type, in a fatty phase containing a polyethylene wax and a hydrogenated jojoba wax, the melting points of which are about 70° C.
More recently, patent application EP 1 159 954 proposes the use, in solid inverse emulsions, of hydrogenated jojoba wax as a dispersion in an aqueous phase, present in a proportion of from 5% to 50% by weight, the emulsion being stabilized with at least one silicone surfactant of polyoxyalkylene type.